1. Field of the Invention
The present invention relates to a carbon-based composite material and a producing method of the carbon-based composite material.
2. Description of the Related Art
A graphite material has a sublimation point of about 3,600° C., so that it is in wide use as a member or the like constituting an inside of an apparatus or furnace such as a silicon single crystal pulling-up apparatus, a high-temperature treating furnace, a nuclear fusion reactor, a nuclear reactor or a hot press apparatus which becomes a non-oxidative atmosphere and a high-temperature environment.
Members used for these applications reach extremely high temperatures, so that they largely deform with thermal expansion. If a member made of the graphite material is arranged in a high-temperature portion and a member made of a different material (for example, metal, ceramic or the like) is arranged on the outside thereof to constitute the apparatus or furnace, a clearance occurs due to the difference in thermal expansion between the graphite member and the different member. Further, even in the case of parts of the apparatus or furnace constituted by only a plurality of graphite members having the same thermal expansion coefficient, if the temperature is uneven, uneven deformation occurs to cause the occurrence of a clearance. If the clearance occurs as described above, the different member constituted by the different material might be uncovered to be exposed to high temperatures. If the clearance occurs between the graphite member and the different member, thermal resistance from the graphite member to the different member might increase to abnormally overheat the graphite member. If the graphite member and the different member are restrained, there is a fear of the occurrence of thermal stress depending on the selection of temperature or material. Accordingly, the graphite member and the different member might be arranged with a clearance provided previously, and from the step before the temperature is applied, thermal resistance to the different member is liable to increase, which might cause the different member to tend to be exposed high temperatures.
In order to prevent the clearance caused by the difference in thermal expansion or the thermal stress, as described in JP-UM-A-62-41446 or JP-A-2000-88985, a technique has been performed in which a carbon-based sheet such as a sheet produced by sheet making of carbon fibers or an expanded graphite sheet is attached between the graphite members or between the graphite member and the different member.
These carbon-based sheets are liable to get wrinkled at the time of attachment to cause uneven in thickness. There have therefore been widely used carbon-based composite members in which the carbon-based sheet is adhered to the graphite member with a heat-resistant adhesive, in order to make it easy to attach the carbon-based sheet to the clearance between the graphite member and the different member.